Apparatus for determining travel time of moving material



D United States Patent [111 3,545,528

[72] Inventor Yi Chung Chang References Cited Franklin Towmhip,Westmoreland County, UNITED STATES PATENTS Pennsylvania 1,971,238 8/1934Sillin 235/15132 2| Appl. No. 719,177 g [22] Filed April 5, 1968 PrimaryExammerAlfred E. Smith [45] Patented Dec. 8, 1970 Attorney-Martin J.Carroll [73] Assignee United States Steel Corporation a mrponuon ofDelaware ABSTRACT: A writing head using electrically conductive ink ismoved laterally across a uniformly moving chart paper a distanceproportional to the distance a steel slab moves from a casting mold to acooling station thereby drawing a timel APPARATUS FOR DETERMINlNG TRAVELTIME distance curve. A reading head consisting of a coil of re- OFMOVING MATERIAL sistance wire connected across a voltage source isadapted to 8 claim" 1 Drawing contact the chart paper and is spaced awayfrom the writing [52] U.S. Cl 164/154, head a distance representing thespacing from the mold to the 324/68, 235/ 15 1 .32, 346/33, 164/282,164/283 cooling station. When the reading head contacts the curve, the[51 I Int. Cl. ..B22c 19/04, writing head acts as a voltage divider andprovides a voltage G04f 9/00 signal proportional to the time requiredfor the slab to travel [50] Fleld of Search 324/68(B), the distance fromthe mold to the cooling station. Preferably a 70(F); 235/151.32, 61.11,92-29(D), 151.1, 151.11, 61(E); 346/33(speed); 164/154 pair of suchdevices operate alternately to provide a continuous voltage signalcontrolling the flow of cooling water.

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$1 I 524 544 I 5 50 I I PATENTED DEC 8 I970 N VE N TOR Y/ CHUNG CHANGAttorney APPARATUS FOR DETERMINING TRAVEL TIME OF MOVINGMATERIAL Thisinvention relates to apparatus for determining the time required for asegment of elongated material to travel between two locations.

In some process lines that operate at variable speeds it is desirable toprovide controls dependent on the time required for a segment ofelongated material to move from a first location to a second location.For example, in quenching a continuously cast steel slab the flow rateof the cooling water is a function of the time required for a slabsegment to travel fro the mold to the cooling station. a

Digital computer systems have been used to control the cooling water ina continuous casting line, but these are operated on length increments,changing the flow once for eachfoot of slab travel. An analogue systemwould be more accurate and provide continuous control of the water flow.

According to my invention a time-distance chart is prepared by plottingelapsed clock time for the length of slab produced.

A line is drawn on alongitudinally moving chart paper by a writing headmoved laterally by a connection to the slab pinch rolls. By sensing thelongitudinal difference between the writing head position and theposition of a line alateral distance away from the writing headequivalent to the distance from the mold to the cooling station, thetravel time for any particular segment of slab to reach the coolingstation is continuously determined.

It is therefore an object of my invention to provide apparatusfordetermining the travel time of a segment of elongated material betweentwo locations.

Another'object is to provide such an apparatus where the speed of theelongated material is variable.

I A still further object is to provide apparatus which develops anelectrical signal proportional to the travel time of segment ofelongated material between two locations.

Stillanother' object of my invention is to provide an apparatus thatcontinuously determines the travel time of elongated material betweenthe two locations.

These and other object will be more apparent after referring to thefollowing specification and attached drawing, in which:

The single FIG. is a schematic view of the apparatus of my invention. 1

Referring now to the drawing, reference numeral 2 represents a mold of acontinuous casting machine (not shown) casting a steel slab S. The slabS leaves the mold at point 4 and is driven by pinch. rolls 6. Coolingwater 8 passes through a control valve 10 to a cooling spray head 12 andover the hot slab S to a drain 14. This is conventional apparatus usedin continuous casting.

A forward drive synchronous transmitter 16 is mechanically connected topinch roll 6 which drives it at a speed proportional to slab speed. Areversedrive synchronous transmitter 18 is mechanically connected to areverse drive motor 22. Transmitters l6 and 18. and motor 22 areconnected to a suitable single phase alternating current driving powersource 20. The transmitters 16 and 18 are those used in Selsyn devicesmanufactured by the General Electric Company, Type BS9890, ModelGEl-l2l29A. Transmitters 16 and 18 are connected to two identical curvefollowers 24A and 24B such as a Brown Curve Follower Model Sl53-l9amanufactured by Minneapolis Honeywell Regulator Company, BrownlnstrumentDivision, Philadelphia, Pennsylvania, modified as hereinafter described.Corresponding components of the curve followers are identified by A or Bsubscripts to reference numerals.

The curve follower 24A includes a chart paper 26A paid off from a roll28A across a flat writing surface 30A and wound up into a roll 32A by amotor 34A. A guide rail 36A is located perpendicular to the direction ofchart travel adjacent the chart paper 26A and roll 32A. A carriage 38Ais movable back and forth along guide rail 36A by synchronous receiver40A such as is used in' Selsyn devices already described. Synchronousreceiver 40A drives carriage 38A in any conventional manner such as by agear and chain drive or a screw drive. Receiver 40A is also electricallyconnected to motor 34A.

Projecting from one end of carriage 38A is a writing head 42A tipped bya pen 44A adapted to write with electrically from carriage 38A is areading head 46A a fixed distance d from the writing head 42A andparallel to it. Reading head 46A has a spirally wound resistance wire48A adapted to make rolling contact on the chart papers 26A. Writinghead 42A and reading head 46A are electrically insulated from eachother.

Synchronous receiver 40A ters l6 and 18 through a three position switch50A. A projection 52A on carriage 38A is adapted to operate againstactuators 54A, 56A and 58A to mechanically actuate switch 50A.Resistance coil 48A of the reading head 46A is connected across a valvecontroller power source 60. One terminal of the valve controller powersource is connected to one terminal of a valve controller 62 and theother terminal of valve controller 62 is connected to pens 44A and 448.

When the continuous castor is .in operation, pinch rolls 6 drive theslab S at various speeds. The rotations of the pinch rolls 6 are pickedup by the synchronous transmitter 16 and a synchronizing signal sent tothe three position switches 50A and 50B. Assume that switch 50A is inthe F position where the forward direction synchronous transmitter 16drives synchronous receiver 40A to move carriage 38A to the left andswitch 503 is in the N position where synchronous receiver 408 isdisconnected from the synchronous transmitters and carriage 38B is atrest in the extreme right position with pen 44B lifted off chart paper26B and the chart paper 263 is at rest. When synchronous receiver 40Abegins to move carriage 38A from its extreme right position motor 34Abegins operating at a predetermined constant speed. The combination ofthe chart 26Bmoving at a predetermined constant speed and the carriagemoving at a speed varied as the pinch roll speeds vary results indrawing a time-distance curve 64. When carriage 38Amoves a distance d,reading head 46A comes in contact with curve 64. Writing head 44A thenfunctions as a voltage divider impressing on the valve controller 62that portionof the voltage of the valve controller power source 60 whichis across the resistance winding 48A between the tip of the reading headand the point where curve 64 contacts the resistance wire 48A. Thus,with proper selection of scales and chart speeds, with carriage speedsvarying as pinch roll speeds, and with distance-d proportional to thedistance from point 4 to cooling station 12, the distance t continuouslyrepresents the time required for the slab to travel from point 4 tocooling station 12. Since the chart paper is moving at a speedproportional to clock time, the voltage applied to the valve controller62 is proportional to clock time and the voltage may be used to indicatethe travel time in any convenient manner. Here, the voltage is used tooperate valve controller 62, which in turn controls valve 10 and changesthe amount of cooling water sprayed on the slab S according to thetravel time of the slab.

By using the two curve followers 24A and 248 a continuous signal isprovided to the valve controller 62. Carriage 38A continues to'movetoward the left until prong 52A contacts actuator 56A which moves switch508 to the F position. Both carriages 38A and 38B then move in theforward direction under the 'control of the forward synchronoustransmitter 16. When prong 52A contacts actuator 54A switch 50A is movedto the R position. Reverse synchronous transmitter 18 then drivessynchronous receiver 40A in the reverse direction moving carriage 38A tothe right, lifting pen 44A from the chart 26A and stopping chart drivemotor 34A. Reverse direction motor 22 drives synchronous transmitter 18fast enough to require substantially less time for full carriage travelin the reverse direction than the expected time for full carriage travelin the forward direction. When prong 52A contacts acis connected toSelsyn transmittuator 58A switch 50A is moved to the N or neutralposition disconnecting synchronous receiver 40A from either synchronoustransmitter 16 or 18. After carriage 3813 has moved a distance d thereading head 46B will contact the curve drawn by pen 44B and begintoproduce a voltage signal to valve controller 62 at the same time thatcarriage 38A has arrived at the extreme left position and stopsproducing a signal with the lifting of the pen 44A at actuator 54Aposition. When prong 5230f carriage 388 contacts actuator 56B carriage38A will begin to move forward and will then again supply the voltagesignal afler moving a distance d.

Whilethe preferred embodiment of my invention is illustrated with awriting head using conductive ink and a rolling contact curve followerit is obvious that other devices capable of receiving and retainingintelligence may be used to plot and follow the time-distance curve 64.Such devices may use a thermal pen and heat sensitive paper, or light orradiation sensitive paper with sensitizing devices for writing andreading, or magnetic tape and sensitizing devices. The magnetic tapecould be an endless belt with an erasing head at a suitable location. a

While one embodiment of my invention has been shown and described, itwill be apparent that other adaptations and modifications may be madewithout departing from the scope of the following claims.

lclaim: Y Y

1. Apparatus for determining the time required for segment of elongatedmaterial to move a fixed distance comprising means for providing a firstsignal proportional to the movement of said elongated material, meansresponsive to said first signal forproviding a time-distance curve ofthe movement of said elongated material, and means connected to saidsecond named means for concurrently generating a second signal relatedto the elapsed time shown on said time-distance curve 'for the fixeddistance.

2. Apparatus according to claim 1 in which the means for providing atime-distance curve includes a surface capable of receiving andretaining intelligence, writing means for placing on said surface acurve having time on a first axis and distance said elongated materialhas moved on a second axis intersecting said first axis and in whichsaidmeans for concurrently generating a second signal includes means forreading from said curve a distance along said first axis correspondingto said 'fixed distance represented along said second axis.

' 3. Apparatus according to claim 2 including a first and a second edgeof said surface, means for moving said moving writing means and saidreading means from said first edge to said second edge while providingsaid curve, means for disabling said writing means and said readingmeans when said writing means reaches said second edge, means for movingsaid disabled writing means and said disabled reading means from saidsecond edge to said first edge, and means for enabling said writing headand said reading head upon reaching said first edge.

4. Apparatus according to claim 3 which includes a second writing means,a second reading means associated with said second writing meansconnected to said connecting means, and means for enabling one writingmeans and its associated reading means while the other writing means andits associated reading means is disabled thereby providing a continuoussignal related to the elapsed time.

of said writing means and its associated reading means as the other ofsaid writing means approaches said first edge of said other surface,means connected to said writing means for disabling said other writingmeans and its associated reading means when said other writing meansreaches said first edge of said other surface, means connected to saidwriting means for movin said other reading means and said otherwritingmeans to sax second edge of said other surface thereby providinga continuous signal related to the elapsed time.

6. Apparatus according to claim 2 in which the means for providing acurve includes a fiat electrically insulated writing surface, means formoving said writing surface inthe plane of said surface in agivendirection at a uniform speed, a carriage adapted to move across saidflat writing surface on a path perpendicular to the direction ofmovement of said fiat writing surface and in a plane parallel to saidflat writing surface, means responsive to said first signal for movingsaid carriage along said path a distance proportional to the distancesaid elongated material moves in said fixed distance, and means mountedon said carriage for writing an electrically conductive curve on saidwriting surface as said flat writing surface and said carriage bothmove; and in which said means for concurrently generating a'signalrelated to the elapsed time includes a voltage source, and reading meansmounted on said carriage spaced away from said writing means a distanceproportional to said fixed distance, said reading means including a barof electrical insulating material with itslongitudinal axis parallel tothe direction of movement of said flat writing surface spirally woundwith a length of resistance wire connected across said voltage sourceand adapted to contact said flat writing surface whereby when saidresistance wire contacts a said curve said writing means functions as avoltage divider to provide a voltage signal proportional to the timerequired for a segment of said elongated material to. move saidfixeddistance.

7. Apparatus according to claim 6 including a second means forprovidinga curve, a second reading means connected to said voltage source andassociated with said second curve providing means, a first and a secondedge of each of said surfaces, means connected to one of said carriageswhen said car: riage approaches one of said edges of one of saidsurfaces for engaging said carriage moving means to said other carriageand to enable said writing means and said reading means of said othercarriage, and means operable when said one carriage arrives as said oneedge for disengaging said one carriage from said carriage moving meansand disabling said writing means and said reading means of said onecarriage and for returning said one carriage to the other edge of saidflat writing surface whereby said voltage signal is continuouslyprovided.

8. Apparatus according to claim 7 including a continuous casting machinefor providing said elongated material, means adjacent said machine forspraying a cooling medium on said elongated material emerging from saidmachine, and means coupled to said voltage signal for controlling saidcooling means.

